The little chap had obviously found something to his liking as he kept surfacing in the same spot. When you see a turtle surface a couple of times in the same spot there is a good chance it has found something to eat. The result of this is that it will probably continue to surface in the same spot so, with a bit of patience, you'll get to see it pop up again and again and again as it takes a breath between bites.
You are more likely however to spot a turtle on the surface taking a breath whilst travelling from spot to spot. In those cases you'll probably only get a couple of seconds to check it out as, for reasons we've discussed previously the tortugas don't like chilling on the surface. Even so its worth noting that they often seem to follow a pattern. This consists of surfacing grabbing a breath and submerging and then surfacing shortly thereafter to take a couple more breaths at a more leisurely pace. Accordingly its worth keeping your eye on them whenever you see one submerge just in case.
Of course its easy for me to say this when I have such clear water but not so easy with the sun's glare and wind or waves disturbing the surface. This is why, when on boats or by water, I'm usually spotted wearing polarised sunglasses. These are an absolute must and with them, if you wander or sail the right areas, you should start seeing not just turtles but sharks, rays, marlin, sailfish, bonefish, tarpon, dolphin, whales, dorado, sea snakes and all manner of other what nots without even getting wet (and possibly whilst downing a cold one)!